added in version 22.1.0
belongs to Maven artifact com.android.support:viewpager:28.0.0-alpha1

ViewPager.PageTransformer

This package is part of the
Android support library which
is no longer maintained.
The support library has been superseded by AndroidX
which is part of Jetpack.
We recommend using the AndroidX libraries in all new projects. You should also consider
migrating existing projects to AndroidX.

public
static
interface
ViewPager.PageTransformer

android.support.v4.view.ViewPager.PageTransformer

A PageTransformer is invoked whenever a visible/attached page is scrolled.
This offers an opportunity for the application to apply a custom transformation
to the page views using animation properties.

As property animation is only supported as of Android 3.0 and forward,
setting a PageTransformer on a ViewPager on earlier platform versions will
be ignored.